I just called what I thought was a very reputable race shop who set my OEM '12 Zx6r forks up with new springs and a Racetech goldvalve kit two years ago. My plan was to arrange for the forks to be refreshed as I thought after two years worth of track days (probably about 20 if I had to guess) I figured it was time; I'm pretty good about preventative maintenance. I mean, if I were going by Dave Moss' maintenance schedule I'd be refreshing "every 8 track days or annually." I was told over the phone that I should save my money because fork oil does not break down... really? That's news to me. Am I missing something?
Whether it loses viscosity or not, it gets dirty and dirty oil does not go through tiny orifices as well as clean oil. So, wrong answer.
Yeah, they told me it doesn't get dirty either!!! This was mostly a sarcastic post .... even I know that fork oil degrades and gets dirty with use. I just can't believe I was seriously told that.
Oil in the forks isn't subject to as much heat breakdown and pressure breakdown as oil in the rear shock. But nevertheless as Rick said up there, the oil gets completely polluted with metal debris and shavings.....and unlike your engine, your forks don't have an oil filter, lol So 2 things go without saying at this point.....rebuild the fork, and don't ever give that shop any more of your business haha
I always thought the oil going across the edges of the shim stack would break it down. Either way, if you ride a lot, change it once a year. It's cheap to do.
Always thought it was the shock that saw less wear and tear, as it's not moving 1:1 like forks since the shock goes through linkage.
Different kind of wear as I understand it. The shock doesn't pollute the oil with particulate matter nearly as quickly as the forks do, but the shock is subject to comparatively higher temps and pressures on the oil which results in it breaking down and losing its viscosity capabilities to resist fading over time......at least that's what I'd read somewhere. The forks don't generally overheat the oil since they are in the open air hitting them and not sitting behind a hot engine/exhaust, so thermal breakdown isn't as much of an issue as all the crud being scraped off by the steel springs sliding against the aluminum inner surfaces of the fork.
I changed the fork seals in my street bike didn't change the copper washer on the bottem bolts, sure enough one started leaking about 2 weeks later. Took it all apart again....the fork fluid was terrible. Looked like the old 20,000 mile fluid that came out 2 weeks earlier. So yes, change often.
